# -*- coding: utf-8 -*-

# Define here the models for your spider middleware
#
# See documentation in:
# https://doc.scrapy.org/en/latest/topics/spider-middleware.html
# from fake_useragent import UserAgent

from fake_useragent import UserAgent
from scrapy import signals
class RandomUserAgentMiddlware(object):
        #随机跟换user-agent
     def __init__(self,crawler):
         super(RandomUserAgentMiddlware,self).__init__()
         self.ua = UserAgent()
         self.ua_type = crawler.settings.get('RANDOM_UA_TYPE','random')#从setting文件中读取RANDOM_UA_TYPE值

     @classmethod
     def from_crawler(cls,crawler):
         return cls(crawler)

     def process_request(self,request,spider):  ###系统电泳函数
         def get_ua():
             return getattr(self.ua,self.ua_type)
         # user_agent_random=get_ua()
         request.headers.setdefault('User_Agent',get_ua())
         pass


class ScrapyCarSpiderMiddleware(object):
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the spider middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_spider_input(self, response, spider):
        # Called for each response that goes through the spider
        # middleware and into the spider.

        # Should return None or raise an exception.
        return None

    def process_spider_output(self, response, result, spider):
        # Called with the results returned from the Spider, after
        # it has processed the response.

        # Must return an iterable of Request, dict or Item objects.
        for i in result:
            yield i

    def process_spider_exception(self, response, exception, spider):
        # Called when a spider or process_spider_input() method
        # (from other spider middleware) raises an exception.

        # Should return either None or an iterable of Response, dict
        # or Item objects.
        pass

    def process_start_requests(self, start_requests, spider):
        # Called with the start requests of the spider, and works
        # similarly to the process_spider_output() method, except
        # that it doesn’t have a response associated.

        # Must return only requests (not items).
        for r in start_requests:
            yield r

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)


# class page_loaded:
#
#     def __init__(self, request, spider):
#         self.request = request
#         self.spider = spider
#
#     def __call__(self, driver):
#         # print(type(driver))
#         # print('call......')
#         return len(driver.find_element_by_xpath('//table[@id="trimArglist"]/tbody/tr/td/div/text()'))
        # img_src =
        # print(img_src)
class ScrapyCarDownloaderMiddleware(object):
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the downloader middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_request(self, request, spider):
        # if('trim.html' not in request.url):
        #     return None
        return None

        # print('process..........')
        # print(request.url)
        # if True:
        #     try:
        #         # browser是webdriver实例
        #         spider.browser.get(request.url)
        #         time.sleep(5)
        #         # WebDriverWait(spider.browser, timeout=30, poll_frequency=3).until(page_loaded(request, spider))
        #         # print(spider.browser.page_source)
        #         # time.sleep(5)
        #         return HtmlResponse(url=spider.browser.current_url, body=spider.browser.page_source,
        #                             encoding='utf-8', request=request)
        #     except TimeoutException:
        #         spider.logger.error("url %s download failed", request.url)
        # Called for each request that goes through the downloader
        # middleware.

        # Must either:
        # - return None: continue processing this request
        # - or return a Response object
        # - or return a Request object
        # - or raise IgnoreRequest: process_exception() methods of
        #   installed downloader middleware will be called

    def process_response(self, request, response, spider):
        # Called with the response returned from the downloader.

        # Must either;
        # - return a Response object
        # - return a Request object
        # - or raise IgnoreRequest
        return response

    def process_exception(self, request, exception, spider):
        # Called when a download handler or a process_request()
        # (from other downloader middleware) raises an exception.

        # Must either:
        # - return None: continue processing this exception
        # - return a Response object: stops process_exception() chain
        # - return a Request object: stops process_exception() chain
        pass

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)
